Process for the continuous production of nitric acid.



A. KLAGES. PROGRESS FOR THE CONTINUOUS PRODUCTION OF NITRIC ACID,

APPLICATION FILED JAN. 25,1913.

1 ggg zy ggg v Patented June 9, 1914.

22 W AF//" W UNITED smarts PATENT A11 To UL Fit/J14,

aneus'r KLAGES, or MAGDEBURG, GERMANY.

I PROCESS FOR THE CONTINUOUS TRCDUCTION OF NITRIC ACID.

To all whom it may concern.-

Be it known that 1, AUGUST KLAons, a subject of the Kingv of Prussia, German Emperor, residing at Magdeburg, Kingdom of Prussia, German Empire, have invented certain new and useful Improve ments in Processes for the Continuous Production of Nitric Acidyof which the following is a specification.

The production of nitric acid from niter and sulfuric acid is usually effected in such a manner that the nitric acid retorts are periodically charged, the hot liquid residue of bisulfate being removed at the end of each operation. This method presents the Well known inconvenience that if the retort, filled with the complete charge, is heated, its contents easily foam and flow over, and further that the material from which the retort is made is submitted to a considerable strain owing to the alternating heating and cooling and owing to the varying effect of the cold and hot acids upon said material. It has already been tried to avoid this inconvenience by pouring into the retort, which is still hotfrom the previous operation, small but equivalent quantities of niter and sulfuric acid in such a manner that, as far as possible, a constant temperature of from 170 to 180 C. is maintained in the retort. It is however necessary to increase for a certain time the heat at the end of each operation so that a temperature of 300 C.

is obtained in order to free the bisulfatc completely from the nitric acid. With such .known methods two superposed retorts are used the upper retort serving for the socalled isothermic distillation at a temperature of over 140, the contents of the upper retort being'then transferred to the second retort in whichthe reaction is completed'at a-temperature of 300. hiany experiments have been made to further divide-this treatment in order 'to obtain a really continuous production of nitric acid. 'It has been proposed, for example, to conduct the mixture of niter and sulfuric acid through a certain number of separately heated retorts with separate distillating devices in such a manner that the bisulfate which is completely freed from the nitric acid flows out of the last retort, the d'istillates being separately drawn off from the separate retorts.

Specification of Letters Patent.

, Application filed January 25, 1913. Serial No. 744,223

Patented June 9, 1914,

I have discovered, that the reaction can be completed in a single retort if almost equivalent proportions of niter and sulfuric acid are poured simultaneously upon the surface of a large quantity of hot molten bisulfate. For this purpose, niter and sulfuric acid are slowly poured into a retort which is. filled up to with molten bisulfate. At the point where these substances come in contact with the acidulated bisulfat-e the newly produced bisulfate owing to its specific gravity, sinks slowly to the hottest part, that is the sole of'the retort, where it is removed by means ofan over-flow device. lfVith this method n'o foaming of the retort occurs. The distillate is condensed \in the usual manner.

With the hcreinbefore described novel process the bisulfate sinks in proportion with its specific gravity which is greatest for bisulfate which is poor of water and completely freed from nitric acid. It is removed from the point where it settles. \Vith the known methods the hot mass becomes free from nitric acid only after it has traveled rather a long way although it is continuously in movement.

The apparatus consists of a large retorta into which the potassium bisulfate is poured through a funnel b fixed in the lid of the retort. If the retort a is heated from the furnace e thebisulfate begins slowly to melt and it is heated up to' about 300" of temperature. If the liquid bisulfate has reached this degree of temperature the niter is introduced into the retort through the funnel Z1 and the sulfuric acid through the pipe 0 which is also fixed in the lid of the retort. These two products are'allowed to the outflow pipe (Z mounted in the lid of the retort and the bisulfate is drawn oil the retort through the inclined outflow tube f, the open lower end of which is situated on the bottom of the retort, its outer end projecting through the side wall of said retort. The level of the molten bisulfate must be maintained at such a height that part of the bisulfate can freely flow out through the overflow pipe I claim Process for the continuous production of nitric acid from niter and sulfuric acid, conflow continuously. The gases escape through sisting in introducing into a, large. retort tion, substantially as desellbed and for the containing a large quantity of hot liquid purposeset forth bisulfate simultaneously niter and sulfuric In Witness whereof I have hereunto set acid, in collecting the distilled nitric acid; my hand in the presence-of two Witnesses.

and in drawing oil continuously While main- 7 AUGUST KLAGES. talnlng a constant liquid level the hotliquid lvitnessest bisulfate which has settled on the bottom HANS EYOLY, of the retort 1n consequence of new formal FRIEDA LADEBECK. 

